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An open-source stethoscope that costs between $2.5 and $5 to produce

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Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#91

Post by ButlerianJihad »

khazhoux wrote: post #89
rustyhancock wrote: post #68

Earlier quoted context omitted.

It's a bit of a head scratcher. It would require abject incompetence on the part of jellybean stephoscope manufactorers for this to make sense. On the other hand the reason Litmann stephoscopes are expensive is target market (doctors), build quality and amortization of cost over probably a decade of use. Stephoscopes are a metanym for doctor, and doctors don't want cheap stephoscopes. It reminds me of the product to…

metanym (taxonomy) A name that is rejected because a valid name (based on another member) already exists for the same group.

  metonymy

  (rhetoric) The use of a single characteristic or part of an object, concept or phenomenon to identify the entire object, concept, phenomenon or a related object.
https://en.wiktionary.org/wiki/metonymy#English

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#92

Post by ButlerianJihad »

sonofhans wrote: post #25
colinbartlett wrote: post #2

I was shocked to see that a "brand name" stethoscope is $100+ and even generic ones are $30.

Years ago I had my blood pressure taken by a nurse; this was when they did it manually, squeezing the pressure cuff bulb by hand and listening with a stethoscope. The doctor came in later, saw the numbers and frowned, and took my pressure again. She (both were women) ended up with a reading much more within my normal range. I asked, joking, “So are you just better than her?” “No,” my doctor replied, “She’s better. Sh…

If you purchase a home BP monitor, it will include instructions on how to take readings, like these:

https://www.heart.org/en/health-topics/high-blood-pressure/u...

Then you will notice when your HCP ignores those instructions, like wrapping the cuff around your shirt-sleeve, or prompting you to talk while the measurement is taken, or allowing you sit with your legs crossed.

BP monitors are often poorly calibrated. The instructions for my home monitors suggest bringing the device into the clinic for calibration, and then the clinician says "we don't do that!"

Manual sphygmomanometer readings won't have an automatic digital readout, and require the human HCP to interpret, announce and record the numbers.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#93

Post by projektfu »

dzhiurgis wrote: post #60
projektfu wrote: post #58

Earlier quoted context omitted.

There are cheap, generic scopes (Sprague-Rappaport types) that are very sensitive but the double tube also causes a lot of noise. There are knock-offs of the Littmann scopes in the market. Then there are the scopes doctors usually buy, which are Littmann, Harvey (made by Welch-Allyn) and Heine, and a few smaller makers. No marketer of a high-quality scope wants to sell it at a $30 or less price point, and if you're g…

How long do they last? Looks like pretty solid piece of equipment, but are they damaged easily or simply clap out after few years?

I have a littmann cardiology 3 I bought in 2010 and the diaphragms wore out in 2019. By that time, they stopped selling official kits for the 3, so I repaired it with an off brand kit and was given a 4 for Christmas. The off brand diaphragm lasted only a couple years. My colleague has had the rubber tubing wear out. They say if you wear a collared shirt it lasts forever hanging on your neck but if it sits on your skin it wears out, and she always wears scrubs.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#94

Post by jstanley »

bluGill wrote: post #38
bsza wrote: post #29

Earlier quoted context omitted.

It definitely doesn’t help that prints from filament printers are very porous, 100% infill or not. Maybe sealing it with epoxy after printing would help?

This seems like another case where the hobby has discovered the 3d printer hammer and forgot that cnc tools (lathe, milling machines) are often better and faster for the job. Or if plastic is what you want injection molding is something you can do on a hobby scale and it is much better (but unlike the others this isn't something you can go from CAD to widget)

In my experience it is very rarely the case that setting up machine tools is faster than 3d printing. And even when it's faster, it's not less trouble. And you have to go and acquire materials in suitable shapes and sizes, and deal with cleaning up chips and offcuts, and deal with deburring and cleaning the part after it's finished.

The 3d printer is always ready and always has material in the right shape. It doesn't make a lot of noise, it doesn't make a lot of waste, the parts come off the machine clean and dry and ready to use. It's really hard to overstate the convenience of 3d printing.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#95

Post by rhyperior »

Johnny555 wrote: post #47
sonofhans wrote: post #25

Earlier quoted context omitted.

Years ago I had my blood pressure taken by a nurse; this was when they did it manually, squeezing the pressure cuff bulb by hand and listening with a stethoscope. The doctor came in later, saw the numbers and frowned, and took my pressure again. She (both were women) ended up with a reading much more within my normal range. I asked, joking, “So are you just better than her?” “No,” my doctor replied, “She’s better. Sh…

I have a much higher BP when I first go to the office than after I'm sitting in the exam room for a bit. Usually they call me back to the hallway where they check my weight, then have me sit in a chair and check my temperature, pulse ox and BP, with maybe only a minute sitting down before they do the BP check. My BP is usually in the "hypertension" range there. But, if they come back to the exam room after I've been…

Same. I measure at home and my relaxed systolic is 30-40 lower than the first measurement in their office.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#96

Post by fluoridation »

rustyhancock wrote: post #68
hex4def6 wrote: post #66

Hmmm. Looking at: https://journals.plos.org/plosone/article/figure?id=10.1371/... I'm not sure I believe the graphs. For example, here's another frequency response chart of some stethoscopes: https://www.researchgate.net/figure/a-Frequency-response-of-... How is it that professional stethoscopes can be that different, and yet this 3D printed one can match a gold-standard one almost exactly? From what I can tell there…

It's a bit of a head scratcher. It would require abject incompetence on the part of jellybean stephoscope manufactorers for this to make sense. On the other hand the reason Litmann stephoscopes are expensive is target market (doctors), build quality and amortization of cost over probably a decade of use. Stephoscopes are a metanym for doctor, and doctors don't want cheap stephoscopes. It reminds me of the product to…

steThoscope

I normally wouldn't comment just to correct a misspelling, but it's pretty consistent and it's an entirely different sound, as well as being what the thread is about.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#97

Post by copperx »

davikr wrote: post #72
rustyhancock wrote: post #68

Earlier quoted context omitted.

It's a bit of a head scratcher. It would require abject incompetence on the part of jellybean stephoscope manufactorers for this to make sense. On the other hand the reason Litmann stephoscopes are expensive is target market (doctors), build quality and amortization of cost over probably a decade of use. Stephoscopes are a metanym for doctor, and doctors don't want cheap stephoscopes. It reminds me of the product to…

Yes, if you're going to be using it for the next 10 years, it is worth going for the more expensive Littman if you can. However, I've heard that there are decent Chinese clones, and honestly I've used those $1 stethoscopes in isolation units and they're not terrible for basic pulmonary auscultation.

But where do they fail? What does a good stethoscope bring? better and clearer amplification?

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#99

Post by KnuthIsGod »

Amazon in India will sell you a pretty reasonable stethoscope for for $3.

Assuming the usual Amazon, distributor and retailer markups, these probably cost around 50 cents to make in China.

https://www.amazon.in/BPL-Medical-Technologies-ST-01-Stethos...

Many poor countries are perfectly capable of manufacturing their own medical equipment

Background: I have worked in hospitals in Bihar & Vellore Tamilnadu, and have university mates, friends and family who worked in hospitals in Mizoram, PNG, Libya, Nepal, Uganda and even South Sudan.

Even the doctors who worked in South Sudan had no difficulty sourcing basic equipment. They did however, have enormous trouble sourcing funding and trained personnel who were willing to work in a potentially lethal situation.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#100

Post by throwaway2037 »

copperx wrote: post #97
davikr wrote: post #72

Earlier quoted context omitted.

Yes, if you're going to be using it for the next 10 years, it is worth going for the more expensive Littman if you can. However, I've heard that there are decent Chinese clones, and honestly I've used those $1 stethoscopes in isolation units and they're not terrible for basic pulmonary auscultation.

But where do they fail? What does a good stethoscope bring? better and clearer amplification?

Yeah, that comment also sent off internal alarms for me also. It would be a great blog post (or YouTube video) for someone to buy a bunch of stethoscopes and objectively test them. I would bet that there is a 10 USD model that is 98% as good as 200 USD models from 3M Littmann. And similar to the neverending arguments about "premium high-fidelity stereo equipment", I bet most doctors cannot tell the difference between the two when the logo/brand is hidden.

BTW: I found the 3M Littmann page on Amazon. The prices are wild: https://www.amazon.com/stores/3MLittmannStethoscopes/page/42...

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